Patent GB-902802-A (GB)
Title: Organic dithiophosphinic compounds and the preparation thereof
IPC: C07F9/04
Filed: 1959-12-11
Abstract: Secondary dithiophosphinic acids, esters and salts of the general formula <FORM:0902802/IV (b)/1> wherein Y is hydrogen, a substituted or unsubstituted ammonium cationic group, a metal cationic group, or an organic ester-forming group and X is <FORM:0902802/IV (b)/2> wherein Ra and Rb are the same or different and are substituted or unsubstituted saturated or unsaturated branched or straight chain aliphatic hydrocarbon radicals in which any given linear carbon chain of said radicals contains from 1 to 18 carbon atoms, and, preferably, said substituted aliphatic hydrocarbon radicals have their substituents on a carbon atom at least 3 carbon atoms removed from the phosphorus atom, saturated or unsaturated substituted or unsubstituted alicyclic radicals, substituted or unsubstituted aryl radicals, and Ra and Rb respectively are attached directly to the phosphorus atom through a carbon atom and wherein R1 to R6 are the same or different and are alkyl groups of 1 to 10 carbon atoms are obtained by (1) contacting a secondary phosphine of the formula: <FORM:0902802/IV (b)/3> with a mixture of sulphur, water and an appropriate basic reagent to form the product in which Y is a substituted or unsubstituted ammonium cationic group or a metal cationic group, (2) and then if desired treating the product of step (1) with acid to form the product in which Y is hydrogen, and if desired converting the product so formed with a basic metallic reagent to form the product in which Y is a metal cationic group, or alternatively, if desired treating the product of step (1) with a metal salt in a cationic exchange reaction to form a product in which Y is a different metal cationic group, (3) and if desired either treating the product in which Y is hydrogen with an ethylenically unsaturated compound or treating the product in which Y is a metal cation with an organic halide to form the product in which Y is an ester group.  The invention also includes the cyclic dithiophosphinic acids, esters and salts of the formula <FORM:0902802/IV (b)/4> wherein Y and R1 to R6 are as defined above.  Th organic ester-forming group which Y may represent may be a substituted or unsubstituted saturated or unsaturated branched or straight chain aliphatic hydrocarbon radical, or a substituted or unsubstituted saturated or unsaturated alicyclic radical or a substituted or unsubstituted aryl radical.  The reaction in step (1) is usually effected at 0-100 DEG C., preferably 15 DEG  to 75 DEG C. and suitable acids for treating the salt product are HCl, dilute sulphuric acid and methane sulphonic acid; the treatment being generally effected at -30 DEG  to 75 DEG C., preferably 10 DEG  to 50 DEG C.  The metal cationic group Y may be an alkali metal, e.g. Li, K or Na; an alkaline earth metal, a heavy metal, e.g. Cu, Hg or Ni or another metal, e.g. Al or Mg.  Suitable bases for use in step (1) are alkali metal hydroxides, alkaline earth metal hydroxides and carbonates and ammonium hydroxide and an inert water-soluble organic solvent e.g. a lower aliphatic alcohol, a cyclic ether, or methyl ethyl ketone may be present.  Atmospheric pressure is normally used in step (1) but higher or lower pressures are also suitable. Specified substituents which may be present in the radicals Ra and Rb are alkoxy, halogen, e.g. Cl, aryloxy, aralkoxy, alkaryloxy, amino, nitro, ureido, sulfo, hydroxyl, carbamyl, acyloxy, carbalkoxy, carboxy and aryl. Examples are given and the products are useful as oil additives and as pre-emergence herbicides.  An example is also given for the preparation of 2,4,6-triisopropyl-1,3-dioxa-5-phosphacyclohexane by the procedure described in Specification 902,801.